#6 Ancient DNA and Mutations

Posted on March 6, 2019 by Diana Roberts


Ancient DNA is the relatively new study of evolution by taking ancient plants, animal and human remains, extracting the DNA and looking for the timeliness of mutations. The speed at which the ancient DNA revolution is moving is exhilarating although the broadness of the tasks are daunting. However, the technology is evolving so quickly that many papers being published right now use methods that will be obsolete within a few years.

The pioneers of ancient DNA spent a large portion of their time traveling the world to remote locations, talking with archaeologists and local officials, and bringing back unique remains that they have analyzed in in their molecular biology laboratories. Today, there is greater communication between source laboratories, molecular biology laboratories and improved laboratories techniques or statistical analysis, obtaining the samples they study through increasingly equal partnerships with archaeologists and anthropologists.

The power of ancient DNA to track the rate at which the frequencies of biologically important mutations have changed is important not just because it offers the possibility of tracking the evolution of specific traits, but also because it provides a previously unavailable tool that can be used to understand the fundamental principles of how natural selection proceeds. A central question in human evolutionary biology is whether human evolution typically proceeds by large changes in mutation frequencies at relatively small numbers of positions in the gnome, as in the case of pigmentation, or by small changes in frequencies at a very large number of mutations, as in the case of height.

Ancient DNA research also reveals pathogen evolution. When grinding up human remains, DNA encounters microorganisms that were in an individual’s bloodstream when he or she died and so were the likely cause of death. This approach proved that the bacterium Yersinia pestis was the cause of the fourteenth-to-seventeenth century CE Black Death, the sixth-to-eighth-century CE Justinianic plague of the Roman Empire, and an endemic plague that was responsible for at least about 7 percent of deaths in skeletons from burials across the Eurasian steppe after around 5,000 years ago. Ancient DNA has also established the history and origins of ancient leprosy, tuberculosis, and in plants, the Irish potato famine. Ancient DNA studies are now regularly obtaining material from the microbes that inhabit us, including from dental plaque and feces, thereby providing information about the food our ancestors ate.

Evolutionary science is on the move!